One hundred-and-twenty performers of all ages and backgrounds, dressed and undressed, posed or moving slightly, cover white-shrouded bleachers rising from a multi-colored marble floor to the base of a giant mosaic panel, a bird’s-eye view of “Breuckelen,” that occupies the high wall at one end of the old Williamsburg Bank Building’s banking floor. Welcome to Sarah Small’s Tableau Vivant-of the Delirium Constructions.